Method of producing micro component

ABSTRACT

To produce a micro component, a resin base ( 1 ) capable of being dissolved by a solvent is formed, physical external force is allowed to act on the resin base ( 1 ) to form a concave ( 3 ) and after a metal is filled into the concave ( 3 ), an excessive metal is removed by grinding and the resin base ( 1 ) is dissolved by the solvent. Consequently, the necessity for lithography apparatuses such as a stepper and an etching apparatus can be eliminated, economy can be improved and production of components having complicated shapes that the lithographic technology cannot easily produce can also be produced.

TECHNICAL FIELD

This invention relates to a production method of micro components to constitute a micro machine.

BACKGROUND ART

Micro components constituting a micro-machine are generally produced by an LIGA (Lithographie Galvanoformung Abformung) process that utilizes a semiconductor production technology.

The LIGA process is a technology comprising the combination of X-ray lithography, electroplating and molding. Those products that are produced is by a method based on an ordinary semiconductor production process have their height limited to several to dozens of microns (μm) whereas the LIGA process can produce three-dimensional products that have height of hundreds of microns (elm) and an aspect ratio of dozens or more.

In the LIGA process, a resist 21 is first applied to an entire surface of a flat substrate 20 as shown in FIG. 7. X-rays are then irradiated from above a mask 22 and are projected to the resist 21 through a lens 23 to sensitize the resist 21. Then, a mask pattern formed on the mask 22 is transferred.

Next, when the resist 21 so sensitized is developed, denatured portions due to sensitization are removed. Nickel, for example, is filled by plating into the portions thus removed and the remaining resist 21 and substrate 20 are etched away, providing a component having the transferred shape by nickel is formed. When a mold is formed by the same method, micro components can be produced by using the mold.

According to the LIGA process, however, masks corresponding to the shapes of micro components to be produced must be individually prepared and a variety of lithography apparatuses such as a stepper, an etching apparatus, and so forth are necessary. Therefore, the installation cost becomes high and economically inefficient. In addition, because the side surfaces of the masking pattern transferred by X-ray lithography are constituted by vertical surfaces, there is also a problem that processing into complicated shapes is difficult.

As described above, the production of micro components involves the problems in that economy must be improved and components having complicated shapes can be formed.

DISCLOSURE OF INVENTION

The invention provides a production method of a micro component comprising a resin base forming step of forming a resin base capable of being dissolved by use of a solvent; a concave forming step of allowing physical external force to act on the resin base and forming a concave having a shape corresponding to a shape of a micro component to be produced; a metal filling step of filling a metal into the concave; a metal removing step of grinding and removing an excessive metal; and a base dissolving step of dissolving the resin base by use of a solvent.

The production method of a micro component described above includes the additional requirements in that the physical external force includes any of a laser beam, an ultrasonic wave, a cutting blade and a grinding wheel; the metal filling step scatters the metal in the concave by sputtering and fills the concave by electroplating; the micro component is a component constituting a micro machine or a molding flask used for producing the component; and the metal is nickel, the resin is an ABS resin and the solvent is acetone.

According to the production method of a micro component constituted as described above, the concave having the shape of a micro component to be produced is formed in the base by the physical external force and after the metal is filled into the concave, the base is removed. Therefore, production of masks and transfer of mask patterns by lithographic technology that have been necessary in the past become unnecessary.

When a laser beam is used as the physical external force, a micro component having a shape in which the side surfaces are not vertical surfaces can be easily produced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a base formed by a base forming step.

FIG. 2 is a perspective view showing a state where a concave is formed in the base by a concave forming step.

FIG. 3 is a perspective view showing a state where a metal is filled into the concave by a metal filling step.

FIG. 4 is a perspective view showing a state where an excessive metal is removed by a metal removing step.

FIG. 5 is a perspective view showing a micro component formed by a base dissolving step.

FIG. 6 is a sectional view showing a mode of forming a concave the side surfaces of which are tapered surfaces.

FIG. 7 is a perspective view showing a lithographic technology according to a conventional method. BEST MODE FOR CARRYING OUT THE INVENTION

A case where a gear to be used as a micro component is produced will be explained as a mode for carrying out the invention by way of example.

To begin with, a resin base 1 having a thickness greater than that of the gear to be formed from a resin is molded (resin base molding step) as shown in FIG. 1. The resin used for molding the resin base 1 must be those which can be later dissolved through a chemical reaction by use of a solvent, and an ABS resin can be used, for example.

Unlike a conventional method that applies a resist and conducts development by X-ray lithography, the invention applies physical external force such as irradiation of a laser beam 2 to the resin base 1 without applying a resist and forms a concave 3 as a cavity having the same shape as that of the gear to be produced as shown in FIG. 2 (concave forming step). Besides the laser beam, ultrasonic waves, cutting blades, etc, can be used as the physical external force. A grinding wheel can also be used depending on the shape of the micro component to be produced.

When the laser beam 2 is used as in the example shown in FIG. 2, the laser beam is irradiated while an irradiation portion 4 or the resin base 1 is being moved in match with the shape of the gear to be produced, and the concave 3 having the gear shape can be formed.

After the concave 3 having a desired shape is formed in the manner described above, a metal 5 as a material of the micro component is filled into the concave 3 as shown in FIG. 3 (metal filling step). Filling of the metal can be performed by a method that scatters the metal by sputtering, for example, and thereafter applies electroplating. Nickel, copper, etc, are used as the metal.

After the metal is filled into the concave 3, an excessive metal is deposited onto the resin base 1 and is therefore removed by grinding (metal removing step). Grinding can be carried out by use of a grinding wheel or a CMP technology. After the excessive metal is removed by grinding, the concave 3 is filled, and the metal 6 having the shape of the concave 3 is exposed as shown in FIG. 4. The exposed surface of the metal 6 is planarized.

Finally, the resin constituting the resin base 1 is dissolved by using a solvent and the gear 7 as the micro component shown in FIG. 5 is formed (base dissolving step). Here, acetone is used as the solvent when the resin base 1 is formed of an ABS resin.

When the micro component is formed in this way, expensive lithography apparatuses such as a stepper are not necessary and masks need not be produced for respective components of different shapes, either. Therefore, the production cost can be drastically reduced.

The example shown in FIGS. 1 to 5 explains the case of the production of the gear the side surfaces of which are vertical surfaces. However, components having complicated shapes can be produced, too, such as in the case where the side surfaces are not the vertical surfaces but are inclined, by adjusting the irradiation angle of the laser beam.

In the case of a micro component the side surfaces of which are tapered as shown in FIG. 6, for example, the laser beam 8 is obliquely irradiated and a concave 10 having taper surfaces 9 can be formed. When the metal is filled into this concave 10, a micro component having the side surfaces corresponding to the taper surface 9 can be formed. In this way, the micro component having the shape that the conventional method using the lithography technology cannot produce can be produced.

The invention can produce not only the micro component itself constituting the micro machine but also a molding flask such as a mold for molding the micro component.

Industrial Applicability

As explained above, the production method of the micro component according to the invention forms the concave having the shape of the micro component to be produced in the base by using the physical external force, fills the metal into the concave and then removes the base. Therefore, the invention eliminates the necessity for the production of masks and the transfer of the mask pattern by the lithographic technology that have been necessary in the past. In other words, the invention can drastically reduce the installation cost and can reduce the production cost.

When the laser beam is used as the physical external force, the micro components the side surfaces of which are not the vertical surfaces can be easily produced. Therefore, those micro components having complicated shapes the production of which has been difficult in the past can be produced easily and economically. 

1. A production method of a micro component comprising the steps of: a resin base forming step of forming a resin base capable of being dissolved by use of a solvent; a concave forming step of allowing physical external force to act on said resin base and forming a concave having a shape corresponding to a shape of a micro component to be produced; a metal filling step of filling a metal into said concave; a metal removing step of grinding and removing an excessive metal; and a base dissolving step of dissolving said resin base by use of a solvent.
 2. A production method of a micro component according to claim 1, wherein said physical external force includes any of a laser beam, an ultrasonic wave, a cutting blade and a grinding wheel.
 3. A production method of a micro component according to claim 1, wherein said metal filling step scatters a metal in said concave by sputtering and then fills said concave by electroplating.
 4. A production method of a micro component according to claim 1, wherein said micro component is a component constituting a micro machine or a molding flask used for producing said component.
 5. A production method of a micro component according to claim 1, wherein said metal is nickel, said resin is an ABS resin and said solvent is acetone.
 6. A production method of a micro component according to claim 2, wherein said metal is nickel, said resin is an ABS resin and said solvent is acetone.
 7. A production method of a micro component according to claim 3, wherein said metal is nickel, said resin is an ABS resin and said solvent is acetone.
 8. A production method of a micro component according to claim 4, wherein said metal is nickel, said resin is an ABS resin and said solvent is acetone. 